1. Field of the Invention
This invention relates to electrodes in the form of a polycrystalline structure of a plurality of separate crystallites dispersed on a substrate, and to the electrochemical manufacture of articles incorporating catalysts. More particularly this invention relates to dispersed catalysts composed of a plurality of separate crystallites formed by electrochemical deposition.
2. Description of the Prior Art
U.S. Pat. No. 3,836,436 of Rivola et al describes a process of forming silver powder by deposition on an anode of graphite, Pt, Pt-Rh, Ti, etc. Current is passed through the electrodes for 3 to 10 seconds followed by off periods of from 3 to 60 seconds. Particles range in size between 30 and 150 nm. U.S. Pat. No. 3,198,716 suggests halving or continuously reducing current density during electrodeposition to improve coercivity in fine particles of magnetic material comprising single-domain elongated magnetic particles.
Barclay et al IBM Technical Disclosure Bulletin Vol. 16, No. 8 p. 2573 (Jan. 1974) describes potentiostatic plating of NiFe plus a small amount of Pd at -950 mV and pure Pd at -500 mV subsequently. Some features of the instant invention which are lacking in the above references are as follows:
(1) The single pulse method of producing much smaller two-dimensional crystallites, (2) The double pulse method of producing crystallites, and (3) The refurbishability of electrodes.